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このRDBについて私は驚くべき闇を見つけたがそこを発表するにはネットは怖すぎる

 このRDBについて私は驚くべき闇を見つけたがそこを発表するにはネットは怖すぎる

YAP(achimon)C::Asia Hachioji 2016midの資料です。

soudai sone

July 03, 2016
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  1. ܕม׵ -- ςʔϒϧͷߏ଄ `hoge` CREATE TABLE IF NOT EXISTS `hoge`

    ( `id` int(11) NOT NULL, `val` varchar(255) NOT NULL ); mysql> SELECT * FROM hoge; +----+--------+ | id | val | +----+--------+ | 1 | ONE | | 2 | 2 | | 3 | Three3 | | 4 | 4Four | +----+--------+ 4 rows in set (0,00 sec)
  2. ܕม׵ mysql> SELECT * FROM hoge WHERE val = "0";

    Empty set (0,00 sec) mysql> SELECT * FROM hoge WHERE val = 2; +----+-----+ | id | val | +----+-----+ | 2 | 2 | +----+-----+ 1 row in set, 3 warnings (0,00 sec)
  3. ܕม׵ mysql> SELECT * FROM hoge WHERE val = 4;

    +----+-------+ | id | val | +----+-------+ | 4 | 4Four | +----+-------+ 1 row in set, 3 warnings (0,00 sec) mysql> SELECT * FROM hoge WHERE val = 3; Empty set, 3 warnings (0,00 sec)
  4. ܕม׵ -- ςʔϒϧͷߏ଄ `hoge` CREATE TABLE IF NOT EXISTS `hoge`

    ( `id` int(11) NOT NULL, `val` varchar(255) NOT NULL ); mysql> SELECT * FROM hoge; +----+--------+ | id | val | +----+--------+ | 1 | ONE | | 2 | 2 | | 3 | Three3 | | 4 | 4Four | +----+--------+ 4 rows in set (0,00 sec)
  5. ܕม׵ mysql> SELECT * FROM hoge WHERE val = 4;

    +----+-------+ | id | val | +----+-------+ | 4 | 4Four | +----+-------+ 1 row in set, 3 warnings (0,00 sec) mysql> SELECT * FROM hoge WHERE val = 3; Empty set, 3 warnings (0,00 sec) ઌ಄͕਺ࣈ ຤ඌ͕਺ࣈ